1 files changed, 90 insertions, 0 deletions
diff --git a/lib/comp/xz.c b/lib/comp/xz.c
new file mode 100644
index 0000000..98d740c
--- /dev/null
+++ b/lib/comp/xz.c
@@ -0,0 +1,90 @@
+/* SPDX-License-Identifier: GPL-3.0-or-later */
+#include <stdbool.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+#include <lzma.h>
+
+#include "internal.h"
+
+typedef struct {
+	compressor_t base;
+	size_t block_size;
+} xz_compressor_t;
+
+static ssize_t xz_comp_block(compressor_t *base, const uint8_t *in,
+			       size_t size, uint8_t *out, size_t outsize)
+{
+	xz_compressor_t *xz = (xz_compressor_t *)base;
+	lzma_filter filters[5];
+	lzma_options_lzma opt;
+	size_t written = 0;
+	lzma_ret ret;
+
+	if (lzma_lzma_preset(&opt, LZMA_PRESET_DEFAULT)) {
+		fputs("error initializing xz options\n", stderr);
+		return -1;
+	}
+
+	opt.dict_size = xz->block_size;
+
+	filters[0].id = LZMA_FILTER_LZMA2;
+	filters[0].options = &opt;
+
+	filters[1].id = LZMA_VLI_UNKNOWN;
+	filters[1].options = NULL;
+
+	ret = lzma_stream_buffer_encode(filters, LZMA_CHECK_CRC32, NULL,
+					in, size, out, &written, outsize);
+
+	if (ret == LZMA_OK)
+		return (written >= size) ? 0 : written;
+
+	if (ret != LZMA_BUF_ERROR) {
+		fputs("xz block compress failed\n", stderr);
+		return -1;
+	}
+
+	return 0;
+}
+
+static ssize_t xz_uncomp_block(compressor_t *base, const uint8_t *in,
+			       size_t size, uint8_t *out, size_t outsize)
+{
+	uint64_t memlimit = 32 * 1024 * 1024;
+	size_t dest_pos = 0;
+	size_t src_pos = 0;
+	lzma_ret ret;
+	(void)base;
+
+	ret = lzma_stream_buffer_decode(&memlimit, 0, NULL,
+					in, &src_pos, size,
+					out, &dest_pos, outsize);
+
+	if (ret == LZMA_OK && size == src_pos)
+		return (ssize_t)dest_pos;
+
+	fputs("xz block extract failed\n", stderr);
+	return -1;
+}
+
+static void xz_destroy(compressor_t *base)
+{
+	free(base);
+}
+
+compressor_t *create_xz_compressor(bool compress, size_t block_size)
+{
+	xz_compressor_t *xz = calloc(1, sizeof(*xz));
+	compressor_t *base = (compressor_t *)xz;
+
+	if (xz == NULL) {
+		perror("creating xz compressor");
+		return NULL;
+	}
+
+	xz->block_size = block_size;
+	base->destroy = xz_destroy;
+	base->do_block = compress ? xz_comp_block : xz_uncomp_block;
+	return base;
+}